Biological pest control in Hishtil propagation nursery

Hishtil is obligated to stick to anything that will ensure we can live in a better world
April 19, 2021
Biological pest control in Hishtil propagation nursery

When growing plants and especially in doing so commercially, like Hishtil does,  one of the most complicated challenges is coping with pests.
The main conventional method to cope with pests is chemical spraying, but over the last few decades and particularly in recent years, there have been more and more reasons to reduce chemical control and shift to environment friendly methods. Environmental pollution, employee safety, hazards for pollinators, strict regulations regarding the use of chemicals and the amount of pesticide residues permitted in consumable products, entire groups of very efficient chemicals that have been banned – all of these have led to developing an alternative way to control pests, "integrated pest management" (IPM).
IPM means pest management in a way that minimizes the use of chemicals and emphasizes natural and low-toxicity methods like pest trapping, low risk pesticides and other practices. A main component in IPM is biological control that is defined as the reduction of pest populations by the use of natural enemies that in this context are also called "beneficials".

There are different kinds of enemies who have different strategies of attacking their prey. Two main strategies are those of predators and parasitoids. Predators are species that feed directly on their prey and by doing so kill them. As they consume a large number of pests, they manage to reduce or even eradicate the entire pest population on the specific plant or crop. Another group is the parasitoids who lay their egg on or within a single pest. The egg hatches, the young stage develops, and in this way it kills the pest from the inside.
An example of a predator is the predatory mite Phytoseiulus persimilis, an obligate predator highly specific to spider mites. Once established, it can keep the plants free of mites. Another predatory mite is Amblyseius swirskii, a generalistic predatory mite used worldwide against whiteflies, mites and thrips. A parasitoid example is the parasitic wasp Aphidius colemani that controls aphids by laying its eggs within the aphid's body.


In the wild, these natural enemies are active, attack pests and create a state of equilibrium between themselves and the pests, reducing the damage caused by the pests and keeping it at a low level. In intensive commercial growing this is not enough. Plants that are to be commercially distributed can't be infested with pests even at a low level like in nature. If these plants, whether whole plants, transplants or cuttings, are to cross borders between countries, the requirements for material that is pest free are much stricter.

This situation leads the grower to integrate several pest control methods: in addition to the use of beneficials they also use pesticides. This integration is very challenging, as most conventional pesticides can't be used because they would harm, disturb or kill the beneficials. Only a limited list of pesticides can be used. Such a list requires extensive knowledge, actual trials, and an updated database covering the influence of the different pesticides on every specific beneficial, in order to confirm that it won't cause harm at any of the life cycle stages.
In some circumstances the beneficials "don't do the job". They can't manage to reduce the pest population. There can be many reasons for this, including environmental conditions such as humidity, day length, temperature, etc., that make it hard for them to become established. Another possibility is the unsuitability of the enemy to the pest (for example, the parasitic wasp Aphidius colemani. Although it is polyphagous and attacks over 40 species of aphids, there are more than 400 species that affect commercial crops, and all of the other species won't be attacked by this wasp). When these things happen, the grower may consider the use of chemicals.

 

 

One of the basic principles for the success of biological pest control is the establishment of the beneficials on the plants. After spreading them on the plants they lay eggs, become established, and the next generation then emerges. To succeed in this establishment process, the beneficials need optimal growing conditions as already mentioned above. In propagation nurseries that grow motherstock plants for the use of cuttings, this becomes more complicated, as the practice of producing cuttings is done by routine trimming of the plants, which means routinely disturbing the beneficials. Therefore, we at Hishtil have to collect data that is unique to our conditions and implement them in our production process. 

Biological control is very challenging anywhere and anytime, and requires a lot of attention to details, growing conditions, agricultural practices, plant stages, etc. In a propagation nursery the challenge is even bigger and in the propagation of herbs or organic herbs it is bigger still. Along the way we may experience successes and failures too, but Hishtil, as a leading company in its field and in order to fulfill its mission "to improve the quality of food and the environment", is obligated to stick to anything that will ensure we can live in a better world.

We would like to acknowledge Bio-Bee Biological Systems the IPM company we work with for their routine assistance and for the photo in this article.

 

For more info visit our site: www.hishtil.com, or contact us at elo@hishtil.com

 

Related Articles